South Korean units restart after probe

02 January 2013

Two units at South Korea's Yonggwang nuclear power plant have been given permission to restart by the country's regulator. Units 5 and 6 had been offline since it was discovered that some parts had been supplied using forged certificates.

Yonggwang (Image: KHNP)

Satisfied with the findings of an investigation into the falsification of the quality assurance certificates, the Nuclear Safety and Security Commission (NSSC) gave permission for Yonggwang unit 5 to restart on 31 December. Today it gave its permission for the restart of unit 6, which required additional safety checks as it had been undergoing maintenance.

The Ministry of Knowledge Economy announced on 5 November that state-owned utility Korea Hydro and Nuclear Power (KHNP), which owns and operates all 23 of Korea's nuclear power reactors, had allegedly been supplied with falsely-certified parts for at least five of them. The company told the ministry that eight unnamed suppliers - reportedly seven domestic companies and one American company - forged some 60 quality control certificates covering 7682 components delivered between 2003 and 2012.

The majority of those parts were installed at Yonggwang units 5 and 6, while the rest were used at Yonggwang units 3 and 4 and Ulchin unit 3. Yonggwang 5 and 6 - both 1000 MWe pressurized water reactors - were immediately taken offline until the parts had been replaced. Parts at the other three units were replaced without taking the reactors offline.

The NSSC has now stated, "It has been confirmed that a total of 13,794 (substandard) parts of 561 kinds have been supplied to the Korea Hydro and Nuclear Power Co under fake warranties over the past ten years and that 6494 of them have actually been used in nuclear power plants."

The commission said that all the substandard parts have been replaced and that all safety checks needed for a restart of the reactors have been completed.

The NSSC intends to introduce measures to improve supply systems, quality controls and external auditing. KHNP also said that it would tighten its audit of nuclear components.